The present invention relates generally to electric door strikes and, in particular, to an electric door strike for use in residential buildings.
With regard to “electric door strike” prior art, the earliest reference found to this type of device is the U.S. Pat. No. 277,628 to Sullivan in May of 1883. Sullivan's patent claims to be an “improvement in electric locks”, indicating that the electric door strike is even older than that. As you might expect from a device of this age, there are literally hundreds of patents on file promoting changes and improvements of every type.
Nearly all prior art patents utilize a “surface mount” design. Only two exceptions were found. The U.S. Pat. No. 4,056,276 to Jarvis describes a latch and strike arrangement, of which the strike is supported via a bored hole in the door frame. The U.S. Pat. No. 5,729,198 to Gorman (mentioned below) describes a solenoid mounted in a tube extending back into the door frame. With these two exceptions notwithstanding, the mounting arrangement according to the present invention and described in this patent application is unique.
With regard to router jigs, router and guide structures of various types have been used for many years to provide guidance of routers and their use in wood working procedures. Such apparatus may be found for example in the U.S. Pat. No. 4,825,920 to Evitts wherein a router structure utilizes a slotted guide plate mounted to a support base for mounting a router thereto.
The U.S. Pat. No. 3,985,168 to Lundquist shows an adjustable router table of rectangular configuration, wherein each of the legs is adjustable relative to one another.
The U.S. Pat. No. 4,630,657 to Obradovich shows a router guide structure utilizing opposed clamping members to secure a workpiece and router structure thereof.
The U.S. Pat. No. 4,552,193 to Armas describes a door frame shaper mounting a router thereto in a guide orientation for shaping door frames in predetermined patterns.
The U.S. Pat. No. 2,862,302 to Lucia describes an adhesive backed “paper-like” template designed to assist an installer in locating boring holes associated with strike installation.
Although each of the above patents provides for a specific need, no prior art has been found that addresses the need to provide fast mounting of an electric strike.
The advent of ‘keyless entry’ in the automotive world has created an interest in developing a similar product for the residential home market. Early efforts included remote controlled deadbolts (as shown in the U.S. Pat. No. D401,565 to Smith), and remote controlled locksets (as described in the U.S. Pat. No. 5,437,174 to Aydin). Though simple and inexpensive, these ‘do-it-yourself’ products were cheaply made and utilized battery power. Their success was short lived.
The U.S. Pat. No. 5,729,198 shows a wireless residential door unlatch system having solenoid/strike plate assembly controlled by a receiver unit which in turn is controlled by RF or other signals. The system can be retrofit into existing residential structures with a single bore into the door jam into which the solenoid/strike plate assembly is mounted. The U.S. Pat. No. 5,729,198 is incorporated herein by reference.
The U.S. Pat. No. 6,005,306 shows a remote control door lock system for residential and commercial building pedestrian doors. The system includes an electrically powered striker plate assembly having a striker plate member moveable between positions for engagement and disengagement with a door latch member. The striker assembly is adapted to be connected to a control unit which supplies low voltage DC power to the striker assembly and includes a radio frequency range signal receiver and a circuit responsive to receiving signals from an operator controlled radio transmitter to effect indefinite or momentary operation of the striker assembly to unlock a door. The control unit circuit includes a first self-latching relay, a selector switch and a second relay for selecting an operating mode of the system wherein the door may be unlatched momentarily (for about 3.5 seconds, for example) or indefinitely until a second signal is transmitted by the transmitter to the receiver. This arrangement has three drawbacks:                1. Many electric strikes are equipped with “intermittent duty” solenoids or magnetic coils (as opposed to “continuous duty”). These coils are made to exert maximum magnetic force, at the expense of heat buildup in the coil. They are limited to 90 seconds of operation in the energized position. If energized longer than 90 seconds they will burn up. The option to leave the striker in the energized position for extended periods as described in U.S. Pat. No. 6,005,306 could result in considerable maintenance to the striker mechanisms.        2. Since users may forget if they locked the door behind them, there should be a position indication of some type near the door (a light, or buzzer to indicate that the door is not locked). The design outlined in U.S. Pat. No. 6,005,306 has no provision for indication. Other than physically ‘trying’ the door, the user has no way to tell if the striker is in the latched or unlatched position.        3. U.S. Pat. No. 6,005,306 provides a maximum of 3.5 seconds of delay in the “momentary” mode. If the user is entering the house with an armload of groceries, it might be good to have more time than that.        